Energy Balance in Modern Agroecosystems; Why and How?

Agricultural Research & Technology: Open Access Journal

Review Article

Agri Res & Tech: Open Access J Copyright © All rights are reserved by Hossein Kazemi

Volume 1 Issue 5 - June 2016

Energy Balance in Modern Agroecosystems; Why and How? Hossein Kazemi* Department of Agronomy, Gorgan University of Agricultural Sciences and Natural Resources (GUASNR), Iran

Submission: May 19, 2016; Published: June 10, 2016

Corresponding author: Hossein Kazemi, Department of Agronomy, Faculty of Plant Production, Gorgan University of Agricultural Sciences and Natural Resources (GUASNR), PO Box 49189-43464, Gorgan, Iran, Tel: +98 17 32245884; Email: *

Abstract Improvements in energy use efficiency are keys for sustainable energy management. Increasing the use of energy inputs in agro systems led to numerous environmental problems like greenhouse gas (GHG) emissions, loss of biodiversity, high consumption of non-renewable energy resources and pollution of the environment. Based on the total energy equivalents of the inputs and output in agroecosystems, the energy ratio (energy use efficiency), energy productivity, net energy and specific energy are calculated for energy analysis. To increase energy efficiency, energy input should be reduced without affecting the crop yield level or increase the production yield. Furthermore, in modern agroecosystems, burning fossil fuels results in the emission of CO2, nitrous oxide (N2O) and methane (CH4) that act as barriers to thermal radiation and prevent it from leaving the earth’s atmosphere. In general, agricultural GHG emissions account for 10-12% of all anthropogenic GHG emissions. According to this, the identification of crop production methods that maximize energy efficiency and minimize greenhouse gas emissions is vital in agro systems. Keywords: Agro ecosystem; Energy analysis; GHG emissions; Renewable energy

Introduction

Discussion

Energy management is an important issue in terms of efficient, sustainable and economic use of energy and it is one of the important elements in modern agroecosystems as it heavily depends on fossil and other energy resources. Energy consumption in agriculture has been increasing in response to the limited supply of arable land, increasing population, technological changes, and a desire for higher standards of living [1,2]. The relation between agriculture and energy use is very close. Irregular use of inputs in agriculture to access the higher amount of yield will along strike rapidly decreasing of natural resources, considerably increasing the amount of contaminants in the environment and enhancement concentration of greenhouse gases [3]. Energy sources used in agriculture consist of two main groups: natural and auxiliary. Natural energy is essential for plant growth and includes solar energy and various forms of chemical energy stored biologically in the soil [4]. To support natural agricultural production processes, auxiliary energy inputs are used by humans so that a given area of land or water produces more than it would do otherwise [5]. Nowadays, modern agroecosystems have become very energy intensive. However, there is a great need to balance the use and availability of energy, especially in the field operations and inputs.

Input-output analysis

Agri Res & Tech: Open Access J 1(5): ARTOAJ.MS.ID.555571 (2016)

The energy input-output analysis is usually used to evaluate the efficiency and environmental impacts of agroecosystems. Researchers have performed detailed energy balances for different crops and farm management systems all over the world in attempts to assess the efficiency and environmental impact of production systems [6]. The energetic efficiency of the agricultural system has been evaluated by the energy ratio between output and input. Human labor, machinery, fuel, fertilizer, chemicals, water for irrigation and seed amounts and output yield values of crops have been used to estimate the energy ratio(energy use efficiency). Energy equivalents are used for estimate the input and output energy. Based on the total energy equivalents of the inputs and output, the energy ratio, energy productivity, net energy and specific energy are calculated using following equations (1-4) [3-7]: Net energy = Energy Output

( MJ ha )

Energy productivity =

−1

- Energy Input

(

Output kg ha −1

(

)

Energy Input MJ ha −1

)

( MJ ha ) ......(1) −1

......(2)

001

Agricultural Research & Technology: Open Access Journal

Specific energy =

) ......(3) ( Grain output ( kg ha )

Energy Input MJ ha −1

Energy use efficiency =

−1

(

Energy Output MJ ha −1

(

Energy Input MJ ha

−1

)

) ......(4)

The direct energy input is the energy consumption of physical energy resources for physical work during field operations. Field operations consume significant amounts of energy in agricultural production, with most being fuel usage [8]. The input energy is divided into direct, indirect, renewable and non-renewable forms. Indirect energy included energy embodied in seed, fertilizers, chemicals and machinery while direct energy covered human labor and diesel fuel are used in the crop production. Improvements in energy use efficiency are keys for sustainable energy management. To increase energy efficiency, energy input should be reduced without affecting the crop yield level or increase the production yield [9]. For example balancing N fertilization with actual crop requirements and adopting minimum tillage are the most efficient techniques to reduce energy inputs [10]. Qiao et al. [11] suggested that in rainfed agricultural systems (maize–soybean–wheat rotation) in Northeastern China, the application of manure supplemented with NPK can simultaneously achieve higher grain yield and lower global warming potential compared to mineral fertilizers alone. Furthermore, integrated pest control techniques should be put in practice to improve pesticide use. It can be expected that all these measurements would be useful not only for reducing negative effects to environment, human health, maintaining sustainability and decreasing production costs, but also for providing higher energy use efficiency [12].

There are both financial and environmental reasons to improve energy use efficiency in agricultural systems. Increasing the use of energy inputs in cropping systems led to numerous environmental problems like GHG emissions, loss of biodiversity, high consumption of non-renewable energy resources and pollution of the environment [10-13]. From an environmental viewpoint, energy use in agriculture is associated with carbon dioxide (CO2) emission which has serious implications for climate change. From a financial viewpoint, energy generally cost money [14]. Analysis of energy consumption for the rice crop in three provinces of Iran showed that energy use efficiency was low and this index varied from 1.39 to 1.67. It is possible to conclude that the energy ratio can be increased by raising the crop yield and/or by decreasing energy input consumption. The results of this study confirmed the importance of diesel fuel and chemical fertilizer consumption on total energy input in these regions. It seems to be possible to reduce energy use, especially fuel and fertilizer, by using better management and more efficient methods [15]. 002

One of the main reasons for high consumption of diesel fuel is a temporal depreciation of machinery. In order to improve the energy consumption as well as reduction of diesel fuel in all cropping systems, it is powerfully suggested that the machinery’s efficiency is raised with new machineries and equipments such as tractor, tiller and irrigation pumps [16]. Mousavi-Awal et al. [17].suggested that for improving energy efficiency in Iran, the farmers should be educated with regard to the optimal use of inputs such as fertilizers, chemicals and irrigation water as well as technologies. In addition, local agricultural institutes have an important role to inform the farmers with respect to more efficient use of energy resources and providing more sustainable agricultural production systems in the region. Connor et al. [18] believe that shortage of energy for agriculture is not a major issue in the foreseeable future, because agriculture uses only a small portion (3-5%) of the total energy consumed in developed countries and less in the world as a whole, but rising prices for energy will bring conservation in all of sectors as well as in agriculture. Significant gains in energy efficiency were a rose in agriculture following the phenomenal increase in energy prices in the 1970s [18]. Greater use of diesel motors, larger tractors, using conservation tillage methods and optimized fertilizer use efficiency were the main causes. Higher yields in line with considerable reduction in embodied energy of labor through greater labor productivity were the main reasons for increased energy efficiency, but it seems that small-scale farming systems could enrich more from conservation tillage methods, especially if further improvements could be achieved to enhance these conservative methods feasibility. Indigenous knowledge-based technologies, especially investment on site-specific machinery could help farmers to match their activities with proper facilities and this could in turn help farmers to reduce diesel fuel consumption in parallel with more conservative farming [15].

Renewable and non-renewable energies

For the growth and development, energy demand in agriculture can be divided into renewable and nonrenewable energies [19]. Renewable energy consists of human labor, water and seed, whereas non-renewable energy includes diesel fuel, fertilizers, chemical, machinery and electricity [15]. Several researchers have demonstrated that the ratio in non-renewable energy is higher than that in renewable energy [3,7,8,12,15,20,21]. The energy in the agriculture sector can be used for providing extensively mechanical energy, heating and lighting, drying and cleaning by direct and indirect. High inputs of diesel fuel and other non-renewable energy sources based on fossil fuel resource would result in more emissions of carbon dioxide, a major greenhouse gas contributing to global warming with extensive impacts on environment [16]. The usage of mechanical energy is more preferred than others and it leads to high consumption of petroleum to obtain mechanical energy. On the other hand, electricity, natural gas and

How to cite this article: Hossein K. Energy Balance in Modern Agroecosystems; Why and How?. Agri Res & Tech: Open Access J. 2016; 1(5): 555571. DOI: 10.19080/ARTOAJ.2016.01.555571

Agricultural Research & Technology: Open Access Journal other sources, such as wind, solar and biomass within renewable energy are less compared to petroleum for providing mechanical energy. Mostly, mechanical energy is needed for agricultural activities, such as land preparation, threshing, harvest, transportation, freight, irrigation, cultivation and milking [22]. Hopper [23] for example, estimated that Canadian prairie agriculture required about 4.5 MJ of non-renewable energy to produce 1 kg of wheat in 1981; but this indicator varies with the cropping system and management practices being used. In Italy, it has been estimated that the energy consumption in agriculture amounts to around 0.42 - 109 GJ year-1, of which 55% is related to arable crops [24]. To approach to sustainable development, our viewpoint on the assessment of cropping patterns should have a tendency to those inputs which will not affect future generation’s welfare and income. It is undeniable that lack of renewable inputs will force us to find alternative energy inputs. This is not the case pending when we could achieve and provide these sources throughout the world. Input application optimization, especially in the agriculture section could be considered as a hopeful case to direct our world in a safe and healthy atmosphere.

Greenhouse gases emissions

Nowadays, Greenhouse gases (GHG) emissions are one of the most important issues. GHG emissions are determined and expressed in CO2 equivalent. GHG emission values from inputs per hectare are calculated using CO2 emissions coefficient of agricultural inputs. The amount of produced CO2 is also calculated by multiplying the input application rate (diesel fuel, chemical fertilizers, pesticides, and machinery) by its corresponding emission coefficient. [25-28]. Burning fossil fuels results in the emission of CO2, nitrous oxide (N2O) and methane (CH4) that act as barriers to thermal radiation and prevent it from leaving the earth’s atmosphere [29]. Agricultural GHG emissions account for 10-12% of all anthropogenic GHG emissions. So, use of different forms of energy and its negative effects are indivisible [25]. Reducing the energy derived from fossil fuels within agricultural systems has important implications for decreasing atmospheric emissions of greenhouse gases, thus assisting the arrest of global warming. The identification of crop production methods that maximize energy efficiency and minimize greenhouse gas emissions is vital [30]. In fact, lower fossil fuel inputs for crop management can determine substantial and longterm GHG emission reductions [31]. Wang et al. [32] reported that reduced inorganic N fertilizer followed by no-tillage would be advantageous for mitigating global warming without decreasing rice-wheat annual rotation crop yields in china. It is explained that in most previous studies the kind of irrigation system (sprinkler or flooding) effects energy consumption and GHG emissions were not considered and the same type of system are intended for different scenarios with different tillage systems. Zhang et al. [33] studied on GHG emissions from rice nursery in China. In this study, CH4 and N2O fluxes were determined from different nurseries under major rice cropping systems. Results 003

showed that flooded nursery and moist nursery decreased total CH4 emissions by 74.2%, 72.1% and 49.6% under the rice–upland rotation cropping system, and the double rice cropping system for the early rice and the late rice, respectively. Generally, three steps are required for successful and efficient reduction of GHG emissions from agricultural production: (1) identification of the most highly polluting farms in terms of GHG, (2) determination of appropriate mitigation options for these farms, and (3) selection of options according to cost effectiveness [34].

Conclusion

The energetic efficiency of the agricultural system has been evaluated by the energy ratio between output and input. It seems to be possible to reduce energy consumption by better management and more efficient methods in the world. This paper suggested and recommend that the consumption of chemical fertilizers, chemical pesticides and diesel fuels is scientifically managed in modern agroecosystems, so that they can be effectively used, resulting in a reduction of soil and environment population, a possible decrease in energy input and a financial saving. In fact, lower chemical inputs for crop management can determine substantial and long-term GHG emission reductions. Ecological intensification is one of the most promising strategies to provide food for foreseen population in the future; therefore, sustainable intensification is tightly dependent on our knowledge of energy consumption state of agroecosystems to provide feasible and reasonable methods for confronting against future food challenges.

References

1. Kizilaslan H (2009) Input –output energy analysis of cherries production in Tokat province of Turkey. Applied Energy 86(7-8): 13541358. 2. Safa M, Samarasinghe S, Mohssen M (2011) A field study of energy consumption in wheat production in Canterbury New Zealand. Energy Conversion and Management 52(7): 2526-2532. 3. Esengun K, Erdal G, Gunduz O, Erdal H (2007) An economic analysis and energy use in stake-tomato production in Tokat province of Turkey. Renew Energy 32(11): 1873-1881. 4. Stout BA (1990) Handbook of energy for world agriculture. London: Elsevier Applied Science. American Journal of Agricultural Economics 73(4): 1302. 5. Food and Agriculture Organization (FAO) (2011) Energy-smart food for people and climate, issue paper.

6. Akpinar MG, Ozkan B, Sayin C, Fert C (2009) An input–output energy analysis on main and double cropping sesame production. J Food Agric Environ 7(3-4): 464-467. 7. Shahan S, Jafari A, Mobli H, Rafiee S, Karimi M (2008) Energy use and economical analysis of production in Iran: a case study from Ardabil province. Journal of Agricultural Technology 4(1): 77-88. 8. Kazemi H, Shahbyki M, Baghbani S (2015) Energy analysis for faba bean production: A case study in Golestan province, Iran. Sustainable Production and Consumption 3: 15-20.

9. Torki-Harchegani M, Ebrahimi R, Mahmoodi-Eshkaftaki M (2015) Almond production in Iran: An analysis of energy use efficiency (20082011). Renewable and Sustainable Energy Reviews 41: 217-224.


Agricultural Research & Technology: Open Access Journal 10. Alluvione F, Moretti B, Sacco D, Grignani C (2011) EUE (energy use efficiency) of cropping systems for a sustainable agriculture. Energy 36(7): 4468-4481.

23. Hopper GR (1984) The energetic of Canadian prairie wheat production 1948-1981. In: Proc. Energex 1984, energy developments: new forms, renewable, conservation. Regina pp. 677-683.

12. AghaAlikhani M, Kazemi Poshtmasari H, Habibzadeh F (2013) Energy use pattern in rice production: A case study from Mazandaran province, Iran. Energy Conversion and Management 69: 157-162.

25. Khoshnevisan B, Rafiee S, Omid M, Yousefi M, Movahedi M (2013) Modeling of energy consumption and GHG (greenhouse gas) emissions in wheat production in Esfahan province of Iran using artificial neural networks. Energy 52: 333-338.

11. Qiao Y, Miao S, Han X, You M, Zhu X, et al. (2014) The effect of fertilizer practices on N balance and global warming potential of maize– soybean–wheat rotations in Northeastern China. Field Crops Res 161: 98-106.

13. Beheshti-Tabar I, Keyhani A, Rafiee SH (2010) Energy balance in Iran’s agronomy (1990-2006). Renewable and Sustainable Energy Reviews 14: 849-855.

14. Biswas WK, Graham J, Kelly K, John MB (2010) Global warming contributions from wheat, sheep meat and wool production in Victoria, Australia e a life cycle assessment. Journal of Cleaner Production 18(14): 1386-1392.

15. Kazemi H, Kamkar B, Lakzaei S, Badsar M, Shahbyki M (2015) Energy flow analysis for rice production in different geographical regions of Iran. Energy 84: 390-396.

16. Ramedani Z, Rafiee S, Heidari D (2011) An investigation on energy consumption and sensitivity analysis of soybean production farms. Energy 36(11): 6340-6344. 17. Mousavi-Avval SH, Rafiee Sh, Jafari A, Mohammadi A (2011) Optimization of energy consumption for soybean production using Data Envelopment Analysis (DEA) approach. Applied Energy 88(11): 3765-3772.

18. Connor DJ, Loomis RS, Cassman KG (2011) Crop ecology: Productivity and management in agricultural systems. (2nd edn), Cambridge University Press, USA. 19. Alam MS, Alam MR, Islam KK (2005) Energy flow in agriculture: Bangladesh. American journal of Environmental Sciences 1(3): 213220. 20. Pishgar-Komleh S, Sefeedpari P, Rafiee S (2011) Energy and economic analysis of rice production under different farm levels in Guilan province of Iran. Energy 36(10): 5824-5831. 21. Ozkan B, Fert C, Karadeniz CF (2007) Energy and cost analysis for greenhouse and open field grape production. Energy 32(8): 15001504. 22. Sayin C, Mencet MN, Ozkan B (2005) Assessing of energy policies based on Turkish agriculture: current status and some implications. Energy Policy 33(18): 2361-2373.

004

24. Borin M, Menini C, Sartori L (1997) Effects of tillage systems on energy and carbon balance in north-eastern Italy. Soil and Tillage Research 40(3-4): 209-226.

26. Snyder CS, Bruulsema TW, Jensen TL, Fixen PE (2009) Review of greenhouse gas emissions from crop production systems and fertilizer management effects. Agriculture, Ecosystems & Environment 133(34): 247-266. 27. Soni P, Taewichit C, Salokhe VM (2013) Energy consumption and CO2 emissions in rainfed agricultural production systems of Northeast Thailand. Agricultural Systems 116: 25-36.

28. Soltani A, Maleki, MHM, Zeinali E (2014) Optimal crop management can reduce energy use and greenhouse gasses emissions in rainfed canola production. International Journal of plant production 8(4): 587-604. 29. Intergovernmental Panel on Climate Change (IPCC) (1997) In: Houghton JT (Ed.), Greenhouse Gas Inventory Reference Manual, IPCC Technical Support Unit, London, UK, Vol. 3.

30. Tzilivakis J, Warner DJ, May M, Lewis KA, Jaggard K (2005) An assessment of the energy inputs and greenhouse gas emissions in sugar beet (Beta vulgaris) production in the UK. Agricultural System 85(2): 101-119. 31. Liu Y, Zhou Z, Zhang X, Xu X, Chen Hao, et al. (2015) Net global warming potential and greenhouse gas intensity from the double rice system with integrated soil-crop system management: A three-year field study. Atmospheric Environment 116: 92-101.

32. Wang B, Liu J, Kim HJ, Webster PJ, Yim SY (2012) Recent change of the global monsoon precipitation (1979-2008). Clim Dyn 39(5): 11231135.

33. Zhang Y, Li Z, Feng J, Zhang X, Jiang Y, et al. (2014) Differences in CH4 and N2O emissions between rice nurseries in Chinese major rice cropping areas. Atmospheric Environment 96: 220-228.

34. Franks JR, Hadingham B (2012) Reducing greenhouse gas emissions from agriculture: Avoiding trivial solutions to a global problem. Land Use Policy 29(4): 727-736.


Energy Balance in Modern Agroecosystems; Why and How?

Recommend Documents